}
	for _, b := range fun.f.Blocks {
		if b == fun.blocks["b2"] {
			t.Errorf("b2 block still present")
		}
		if b == fun.blocks["b3"] {
			t.Errorf("b3 block still present")
		}
		for _, v := range b.Values {
			if v == fun.values["cond"] {
				t.Errorf("constant condition still present")
			}
		}
	}
}

func BenchmarkDeadCode(b *testing.B) {

	defer a.Free()

	const iValue = 10

	i := arena.New[int](a)
	*i = iValue

	if *i != iValue {
		// This test doesn't reasonably expect this to fail. It's more likely
		// that *i crashes for some reason. Still, why not check it.
		log.Fatalf("bad i value: got %d, want %d", *i, iValue)
	}

	const wantLen = 125
	const wantCap = 1912

	sl := arena.MakeSlice[*int](a, wantLen, wantCap)
	if len(sl) != wantLen {

```Python hl_lines="1  7-12  19-20"
{!../../../docs_src/dataclasses/tutorial001.py!}
```

This is still supported thanks to **Pydantic**, as it has <a href="https://docs.pydantic.dev/latest/concepts/dataclasses/#use-of-stdlib-dataclasses-with-basemodel" class="external-link" target="_blank">internal support for `dataclasses`</a>.

package main

import "fmt"

type i5f5 struct {
	a, b          int16
	c, d, e       int32
	r, s, t, u, v float32
}

//go:noinline
func spills(_ *float32) {

}

//go:registerparams
//go:noinline
func F(x i5f5) i5f5 {
	y := x.v
	spills(&y)
	x.r = y
	return x
}

func main() {
	x := i5f5{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}
	y := x
	z := F(x)

# cmd/doc should use GOROOT to locate the 'go' command,
# not use whatever is in $PATH.

# Remove 'go' from $PATH. (It can still be located via $GOROOT/bin/go, and the
# test script's built-in 'go' command still knows where to find it.)
env PATH=''
[GOOS:plan9] env path=''

go doc p.X

-- go.mod --
module example

go 1.19

require example.com/p v0.1.0

replace example.com/p => ./pfork
-- example.go --
package example

mkdir $GOCACHE

# Building a trivial non-main package should run compiler the first time.
go build -x -gcflags=-m lib.go
stderr 'compile( |\.exe"?)'
stderr 'lib.go:2.* can inline f'

# ... but not the second, even though it still prints the compiler output.
go build -x -gcflags=-m lib.go
! stderr 'compile( |\.exe"?)'
stderr 'lib.go:2.* can inline f'

# Building a trivial main package should run the compiler and linker the first time.

	MULL	CX
	SHRL	$22, DX
	MOVL	DX, BX
	IMULL	$10000000, DX
	MOVL	SI, CX
	SUBL	DX, CX

	// DI = sec/100 (still)
	// BX = (nano/100%1e9)/1e7 = (nano/1e9)%100 = sec%100
	// CX = (nano/100%1e9)%1e7 = (nano%1e9)/100 = nsec/100
	// store nsec for return
	IMULL	$100, CX
	MOVL	CX, nsec+8(FP)

	// DI = sec/100 (still)
	// BX = sec%100
	// construct DX:AX = 64-bit sec and store for return
	MOVL	$0, DX
	MOVL	$100, AX
	MULL	DI

**FastAPI** is already being used in production in many applications and systems. And the test coverage is kept at 100%. But its development is still moving quickly.

New features are added frequently, bugs are fixed regularly, and the code is still continuously improving.

app = FastAPI(
    servers=[
        {"url": "/", "description": "Default, relative server"},
        {
            "url": "http://staging.localhost.tiangolo.com:8000",
            "description": "Staging but actually localhost still",
        },
        {"url": "https://prod.example.com"},
    ]
)


@app.get("/foo")
def foo():
    return {"message": "Hello World"}


client = TestClient(app)


def test_app():

# (But asking for exactly v2.0.0+incompatible should still succeed.)
go list -m github.com/russross/blackfriday@v2.0.0+incompatible
stdout '^github.com/russross/blackfriday v2\.0\.0\+incompatible$'


# However, if the latest compatible version does not include a go.mod file,
# +incompatible versions should still be listed, as they may still reflect the
# intent of the module author.